1. Field of the Invention
The present invention relates to AC cabling or power distribution units used for delivering AC power to an audio or video entertainment system or an audio or video recording system, and also to an electrical distribution system used for live music or video performances.
2. Background Discussion
AC power transmission is typically transmitted as a sine wave at a frequency of 50 or 60 hertz. Power lines are susceptible to EMI (electromagnetic interference) and RFI (radio frequency interference) due to the fact that power lines are relatively long and are generally not shielded. The EMI/RFI noise transmitted along with the power line frequency can interfere with the proper operation of electronic equipment. It is especially harmful to the sonic performance of high-end audio and video equipment. It is therefore desirable to substantially reduce or entirely eliminate EMI/RFI before it enters an electronic device.
There are many power conditioners and power strips designed to reduce the various forms of noise. The several fundamental design methodologies achieve this noise reduction, usually using filtering, isolation and/or absorption. Filtering methods include the use of inductive components, such as series coils, to limit the frequency bandwidth. Exemplary devices are low-pass filters. Another filtering method involves the use of capacitive components, such as power capacitors and by-pass capacitors, connected in parallel to the power line conductors. This device configuration creates a high-pass shunt. Inductive and capacitive methods are often used in conjunction to create filter networks such as L, T and pi filter networks.
Isolation methods involve the use of power transformers. These transformers are usually 1:1 power transformers, meaning that they neither step up nor step down applied voltage. The transformer has an electrostatic shield between the primary and secondary windings that prevents noise from passing from the primary to the secondary output.
Another common method to reduce power line noise involves the use of a ferrite material. Ferrite beads are commonly used to create a low pass filter, similar in function to a coil. However, a coil stores energy within its electromagnetic field and returns the energy to the conductor. In contrast, a ferrite material actually absorbs electromagnetic energy within its molecular structure and converts the energy to heat within that structure. Therefore, a ferromagnetic substance absorbs noise. Ferromagnetic materials are primarily composed of iron, which is commonly alloyed with other magnetic metals to create various frequency-specific ferrite materials.
All of these methods are used individually or in various combinations to create power conditioning products designed to reduce EMI/RFI. Each method has relative advantages, but all have corresponding negative effects when used for high-end audio or video systems. Inductive methods and isolation transformers tend to limit the transmission of instantaneous current, while capacitors tend to ring when excited by noise transients that are at their points of resonance, the latter problem requiring damping to bring stability to the circuit. Since ferrite beads usually operate in the megahertz to gigahertz frequency ranges, they do not limit instantaneous current delivery. However, audiophiles skilled at discerning subtle musical characteristics report that ferrite materials negatively impact the sound quality.
The last method of noise reduction involves the use of ferroelectric materials. A ferroelectric material is not composed of metal but rather non-conductive crystalline substances. These substances react at a molecular level when exposed to an electric field. They will tend to absorb electric field energy and convert it to heat within its structure, just as a ferromagnetic material absorbs magnetic field energy. Similar to ferromagnetic materials, ferroelectric materials operate primarily in the megahertz to gigahertz frequency ranges and are therefore effective in reducing EMI/RFI in these ranges. However, this method is not commonly used because it requires large amounts of material to achieve the same results obtainable with a small amount of ferromagnetic material. However, as reported by audiophiles that are skilled in the art, in the context of a high-end audio systems, ferroelectric materials, when used for power line noise reduction, tend to have superior sonic characteristics.
Gabriel U.S. Pat. No. 6,545,213 demonstrates the use of ferroelectric substances for the purpose of reducing high frequency noise that may be present on AC power transmission lines, as in a power cable or within a power conditioner. Gabriel '213 describes power wires contained within a non-conductive, flexible tube that is filled with a ferroelectric substance. As described in Gabriel '213 the effectiveness of the electric field coupling to the ferroelectric substance is largely determined by the diameter of the power wire within the non-conductive tube and the quantity of ferroelectric material used. [Gabriel '213 is incorporated in its entirety by reference herein.]
The present invention improves on the coupling of the electric field over Gabriel '213 by significantly increasing the contact area between the ferroelectric substance and the electric field chamber.
The foregoing reflects the current state of the art of which the present inventor is aware. Reference to, and discussion of, these patents is intended to aid in discharging Applicant's acknowledged duty of candor in disclosing information that may be relevant to the examination of claims to the present invention. However, it is respectfully submitted that the background art does not disclose, teach, suggest, show, or otherwise render obvious, either singly or when considered in combination, the invention described and claimed herein.